418W compression reading?

[brettco]

I have a sprint car with 15.2 to 1 that has 170 cranking comp. and a stock 02 mustang that is 9.5 to 1 thats 175psi- surprised me.Its all about the cam. My pump gas stroker 472 fe is 155psi

[donraye]

Originally Posted by brettco

I have a sprint car with 15.2 to 1 that has 170 cranking comp. and a stock 02 mustang that is 9.5 to 1 thats 175psi- surprised me.Its all about the cam. My pump gas stroker 472 fe is 155psi

That's pretty interesting considering the very diffferent engines and yet the not so different compression readings. I would have expected higher and more differing readings, at least on the stroker and the sprint car. But I'm not at all "experienced" nor a pro. so that's why I ask this stuff.
This cam is a hydraulic roller and what I would call a "moderately" agressive street performance cam. The gross lift is .555 and .576 with 1.6 rockers and the duration @ .006 tappet of 287 and 293. So not a "monster" cam by any means.
Thanks for the comparisons and information it will help give me some idea of a range although I know it will not be in any way exact. Still it's a start to knowing what I might expect.
I would assume that if there is much leakdown, as due to improper valve lash, that the numbers would show a "considerable" loss of pressure not just a 20 or so pound one. However this is my very first build so I am only guessing about that. It might be a more subtle difference than I think, and therefore not a good indicator of anything at all.
I did adjust the rockers as the books say by having them at the point I could feel the slightest resistance while rotating the push rods then I gave them 1/3 turn more(a compromise between the 1/2 for street and 1/4 for racing that all the books called for) and locked them there. The lifters were full of oil and were not collapsed and I rechecked the rocker adjustments after starting and running the engine for a few minutes to make sure that it had not changed due to any possible "pump-up" of the lifters. It remained the same so I think all is fine. Just wanted to make any other confirmations I can with what tools I have before running the engine for a longer time and under load.
It will be going to the chassis dyno for a complete tune ASAP, so they can fine tune everything then.
Thanks again, D.